Band-saw tensometer



R. C. BERRY.

BAND SAW TENSONIETER.

APPUcATloN FILED MAR.8.1919.

Patented Dec. 2, 1919.

@Meme/1%,

UNTTED sTATEs PATENT oEEicE.

ROBERT C. BERRY, OF INDIANAPOLIS, INDIANA. ASSIGNOR TO E. C. ATKINS &COMPANY, OF INDIANAPOLIS, INDIANA, A CORPORATION OF INDIANA.

BAND-SAW TENSOMETER.

Specification of Letters Patent.

Patented nee. 2, i919.

Application led March 8, 1919. Serial No. 281,415.

T0 all whom it may concern: n

Be it known that I, ROBERT (l. BERRY, a citizen of the United States,residing at Indianapolis, in the 'county of Marion and State of Indiana,have invented a new and usefill Band-Saw Tensometer, of which thefollowing is a specification.

In the operation of band-saws, they tension given the saw has usuallybeen a matter of guess-work, and frequently the adjustment for the sawtension has been made too tight or too loose; in fact, it is a questionwhether the saw tension is not usually wrong, since there is noconvenient means for indicating it.

It is the object of my invention to provide a tensometer for indicatingconstantly and automatically the tension of the band saw, so that suchtension may be made and maintained anything desired, and so that in casethe tension is increased from any cause the tensometer will give anexactindication thereof and thus guard against breakage.

In accomplishing this object, I provide an offset in the post connectingthe bearings for the upper and lower band wheels, so that by tlexure atthis offset the distance between two points on this post is variedinversely as the tension of the band saw, which is carried by such twoband wheels; so that by providinganother member which in independent ofsuch iexnre, and connecting it and the post through an indicatingdevice, the flexure of the post offset and therefore the tension of thesaw are indicated.

' I have shown my tensometer in connection with a swing -band-sawmachine such as is shown in my prior Patent No. 1,287,193, grantedDecember 10, 1918, in whichthe post connecting the two band-wheelbearings is provided with an offset in the plane of the -work uponwhich` the saw operates so that the post will clear the work, and thesame offset isA used for obtaining the flexure whichl operates thetensoineter; but my tensometer is not limited to a swinging band-sawmachine, as it is applicable to band-saw machines of any type.

The accompanying drawing illustrates my invention: r.Figure l is aperspective view of a band-saw machine equipped with my tensometer, onlysuch parts of the band-saw machine being shown as are necessary -to theunderstanding of the action of such tensometer; and Fig. 2 is a detailof the adjustment for the bearing for the upper band wheel.

The band saw 10 is carried by upper and lower band wheels 11 and 12,which are ltension of the band saw 10; as shown, this bearing 13 ismounted on the upper end of a screw 16 having a guiding mounting in theupper end of the post 15 and cooperating with an internally threadedthrust wheel 17 which presses against the upper end of such post, as isclear from Fig. 2, so that, by tui-nina the thrust wheel 17 the distancebetcvlveen the bearings 13 and 14 may be varie The post 15 is providedat an intermediate point with a U-shaped offest portion 20. In swingingband-saw machines, where the work is stationarily supported on the table21, this offset 2O permits the post 15 to clear the work as the swingingmember of the band-saw machine is swung back and forth,

as explained in my aforesaid patentsuchpost and the band saw formingpart of suoli swinging member.

A U-sha'ped member Q2, made U-shaped for this same reason of obtainingclearance, lies closely beside the offset portion 20. This U-shapedmember 22 is fastened to the post '15 at its lower end, as by screws 23;but is free of suoli post elsewhere, so that it does not artake of anyeXui-e which mav occur in t e offset portion 20 of the post. Iounted inthe upper free end of the U-shaped member 22 is a thumb-screw 24, foradjusting the indicator; and the upper end of this thumb-screw Q4presses against the under face of a pointer pivoted on the post 15 at apoint 2G, from which the thumb-screw 24 is not far distant, so thatrelatively slight movements between the point 26 and the thumb screw 2-1produce relatively large movements of the free end of the pointer 2.5,which free end swings over a suitable scale 27 carried by the post 15.

In operation, as the tension of the saw 1() is varied, by the adjustmentof the thrust wheel 17 or in any other manner, an increase vin suchtension produces a flexure of the ott'- set portion Q0 of the vpost 15to bring the point 2G and the point to which the screws :23 are attachedcloser together, while a delll) vbeing provided with an provided tensioncauses the elasticity portion 20 to separate sulch point 26 from thescrews 23. As the U- shaped member 22 does n'ot partake of this flexureof the U-shaped portion 20, this variation in the height of the point 26with relation to the screws 23 involves a variation in the relativeheights of the point 26 and the thumb-Screw 24, Iwhich causes the freeend of the pointer 25 to move over the scale 27 in accordance with suchflexure; the pointer rises on such scale as the tension of the saw andthe flexure o-f the U-sha ed portion 20 increase, and vice versa. husthe height of the pointer 25 on the scale 27 indicatesv the tension ofthe saw l0, and Guides the operator in his adjustment of such tension byt'he thrust wheel 17, so that the proper tension may Ibe obtainedWithout danger of ybreaking the saw; In oase the tension 'of the sawdeparts from the desired value in operation, thls is immediatelyindicated by the pointer 25, so that the operator may make propercompensation therefor by manipulating the thrust wheel 17.

crease in such of said offset I claim as my invention:

In a band-saw machine, the combination oftwo band wheels, a post inwhich said wheels are revolubly supported, said post offset portion 'befa member fixed to said off'set portionother side thereof,

tween said two wheels, said post at one side of and free therefrom atthe andan indicator responsive to relative movel ments between the reeend of said member and an Iadjacent part of said post.

2. In a band-saw machine, the combination of two band wheels, bearingstherefor, a post in which said bearings are mounted, means for adjustingthe distance separating said bearings on said post, said post beingbetween said bearings with a portion which is variable in length uponvariations in the tension of the band saw carried by said two bandwheels, member fixed to .said post at one side of said variable-length Yportion and free from such variations in length, and an indicatorresponsive to variations in the relative positions of the other side ofsaid variable-length portion and of said member.

3. In a band-Saw machine, the Combination of two band whe-els, bearingstherefor, a post in which said 'bearings are mounted, means foradjusting the distance separating said bearings onpsaid post, said postbeing provided between said bea-rings with a por'- tion which isvari-able in length upon' variations in the tension of by said two bandwheels, and an indicator which is operable by variations in the lengthof said variable-length portion.

4. In a band-saw machine, the combination of two band wheels,

the band Saw carried j .fourth day 'of March, A. D

bearings therefor, a post in which `said bearings are supported, meansfor adjusting the distance between said bearings on said post, saidpostbeing provided between said bearings with a laterally offset portionwhich by reason of its shape will vary in length upon variations in thetension of the band s-'a-w carried by said band wheels, a memberconforming in genenal to the shape of said offset portion and attachedto the post at one end only of said offset portion, anid an indicatorinterconnecting the other/end of said offset portion and the freeendflofsaid member so that it is operated by variations in the length ofsaidoffset portion.

5. In a band-saw machine, the combination with the two band wheels andt'heir bearings, of a member connecting saidv two bearings anld providedwith a portion which is variable in length by fieXure upon variations inthe stress exerted between said bearings by the tension of theassociated band saw, and an indicator which is operable by variations inthe length of said variablelength Iportion.

6. In a band-saw machine, the combination of two lband Wheels, a post inwhich said Wheels are revolubly' supported, means for adjusting thedistance between the supporting points for sai'd wheels along said tpost, said postfbeing provided with an offand an indicator responsive tosuch varia tions in length by fleXure.

In a band-saw machine, tion of two band wheels,

the com'binaa post in which said wheels are revolubly'supported, saidVpost being variable in length by fleXure under the stress exe Ibetweensaid band wheels by the tension of the'associated band saw, an indicatorresponsive to such variations in length by fiexure, and means foradjusting the distance along said post of the points of support for saidtwo band wheels.

In witness whereof, I have hereunto set my hand at Indianapolis,Indiana, this one thousand nineteen.

nine hundred and ROBERT C. BERRY.

